It once had a children's choir sing about arson and bullying in a mall. It was a stunt for a Flemish advice line for parents of out of control children.

According to DGM's Marc Wellen, it only took the agency five days to come up with the TNT idea.

"It's not that we do this for every client, it is most appropriate for international brands [so that it can spread]," Wellen told BI. "Secondly, you have to do this only if the brand is willing to have side effects of the message."

DGM first thought it would do a stunt about cowboys versus Indians.

In the end, DGM decided to go bigger: An unsuspecting bystander would be persuaded to push a big red button that unleashed a dramatic scene incorporating football players, cops, robbers, convicts and paramedics—all of whom could be linked to a dramatic TNT show.

There were no storyboards, just brainstorming. TNT approved of the idea on Feb. 24, after just one phone call.

It also probably wouldn't have worked in America. Adult Swim tried a stunt in 2007 in which the network placed magnetic lights on bridges and buildings around Boston. The result: numerous calls to the bomb squad.

DGM went with a "a little town in Belgium on a square where nothing really happens."

The team rehearsed pieces of the stunt at 7 a.m. without the sound, so as not to wake the townfolk with gunshots.

The stunt men and women spent the day blocking fistfights and gunfights, and riding around motorcycles in red lingerie. All in a day's work.

Here's the cast and crew getting briefed.

"At around noon we were ready for a complete dry run," Wellen said. "We did it 11 times in a row, but allowed 30 minutes between each performance."

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Cafe patrons around the square were treated to a few runs of the stunt. DBM's crew asked them not to ruin the surprise for others.

Duval Guillaume Corporate

Eleven different unsuspecting people pressed the big red button and were immediately surrounded by chaos.

Security was ready to intervene, but wasn't needed. "I was surprised that the people pushing the button didn't run away; they were too surprised by the action unfolding in front of their eyes," Wellen said.

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Camera teams were hidden throughout the square to capture everyone's reactions.

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"We were very confident in the results, but were also absolutely surprised by the speed it took," Wellen said. "We weren't ready for it."

Duval Guillaume Corporate

The ad was shot on March 3 and posted online on April 11.

It had 4.5 million views in 24 hours, and 23 million in one week. Belgium has a population of 11 million.

"We had a seeding strategy to spread it that we didn't even use," Wellen said.

"We said we were going to write to blogs, send it to marketing blogs, but they picked it up themselves," Wellen said. When the video premiered on April 11, it was only posted on TNT's YouTube account, DGM's Facebook page, and the Facebook's of enthusiastic DGM employees.

The media picked it up from there. DGM says that it did no additional promotion.

After only a month, the video has almost 33 million views. Here's the ad: